The Sound
Contents
Now how do you describe differences between an already very good USB card – the Jcat USB XE – and the same card with a Master Clock Upgrade? Tricky… after all, it’s subtle. But audible and noticeable.
Attack and openness
Now we cannot quickly switch A / B between the “regular” USB card and the USB card with Master Clock. However, we know the reference system well and actually hear pretty quickly that the version with the Master Clock shows a bit more openness. The whole thing is a bit more airy. It’s subtle, but noticeable to someone who knows their system well.
Also, the whole thing seems a bit tighter. More attack, or perhaps better transient information. That in itself is not crazy if the clock in the dac gets an upgrade. But on a USB card it is remarkable … and yet: it really seems to play a little tighter. Again subtle: but noticeable for someone who knows his system well.
Now it is important to know that we are playing with a Mutec MC3+ USB with REF10-SE120. This reclocker will disguise some of the effect, because the Mutec already “fixes” a lot of problems by sitting as an interface between the Alpha PC and the Sonnet Pasithea dac. Enthusiasts who connect the PC directly to their dac will most likely hear more impact. The fact that we actually notice differences now, however, certainly says something about the effect of the clock on the USB interface…. fascinating.
Smooth
The highs also feel a bit smoother we feel. On Portishead Roseland NYC, less grain is audible on the high-hats. This makes the whole feel a bit calmer. However, without losing energy and drive.
Overall
Overall, we can say that the Master Clock gives a subtle but audible improvement. We hear a bit more air and flow and a bit tighter timing behavior (more attack, better transients?).
Is this subtle step worth 1200 Euros? We leave that up to you. After all: we can’t look into your wallet and what is a subtle difference for one person is not noticeable for another, or just a gigantic improvement for yet another person…. It is not only personal, but it also depends on the system.
I posted it on your FB page, but will post here as well 🙂
Thank you for the review 🙏 There is an upgraded version of the USB Card coming in June – USB XE EVO – which will accept the Master OCXO Clock via SMA connector. There are other improvements too (to be disclosed when the card becomes available). One small comment on the Master OCXO Clock review: the product can be ordered at a custom frequency (e.g 10MHz). We inform about it on our website. Again, thank you for taking the time to review our product
Regarding the question from Gordon: the chipset that’s used on the card requires 20MHz. There is no PLL on the USB Card XE.
Best regards,
Marcin
Jaap,
The really big question here is why 20Mhz? I have designed 100’s of USB products and they pretty much all fall in the 12Mhz or 24Mhz (early ones 6Mhz). Using a PLL on 20Mhz to align with the required frequency for a USB card would not be hard. All theory aside the idea that the out going frequency of a PLL inherits the jitter of the main clock is never a reality.
I say the same thing to all these companies using 10Mhz clocks in audio. Really??? There are probably some real nice oscillators out there at 24Mhz that could be divided down to 12Mhz if required that would do a real nice job if used with a low noise power supply and good lay out techniques.